Colorado's Senate candidates are preparing for a possible recount in a neck-and-neck contest, with neither contender declaring victory by early Wednesday.

Democratic Sen. Michael Bennet and Republican Ken Buck were within a few thousand votes of each other with nearly 1.5 million ballots counted. Thousands of provisional and write-in ballots remained to be counted.

As of 8 a.m, Bennet had regained the lead votes, with just 6,487 votes seperating him from Bucks. About 87 percent of precincts were reporting.

Some projections showed the race could end up within half of 1 percentage point, which would trigger an automatic recount under Colorado law. Both Democrats and Republicans said last week they'd be ready for a possible recount.

Bennet, 45, is seeking his first full term after being appointed to the seat last year. Before becoming senator, Bennet was the Denver public schools superintendent. He replaced Sen. Ken Salazar, President Barack Obama's interior secretary.

Buck was among the first Republicans to announce he'd try to unseat Bennet. The 51-year-old prosecutor from Weld County in northern Colorado courted tea party groups with a promise to cut spending and push for a federal balanced budget amendment. He defeated a better-known and better-funded Republican in the GOP primary, former Lt. Gov. Jane Norton.

The race attracted more out-of-state campaign money than any other Senate contest this year - almost $33 million, according to the Washington-based watchdog group Sunlight Foundation.

"We're not ready to make an announcement, and we won't until we are certain that every ballot that should be counted is counted."

Final results could take days. County elections officers have until Nov. 16 to count provisional ballots, and the secretary of state's office has until Nov. 26 to verify the full vote and order a recount.

"This year it's mainly about the parties," said Joe Ruth, a 41-year-old software architect from Louisville, who voted for Bennet. "I normally vote Democratic, and I'd like them to keep control of Congress."

But Todd Lovrien, 47, a small businessman who voted a straight Democratic ticket in 2008, voted for Buck.

"I was conflicted about Buck because of all the crappy ads against him, but I just thought Bennet didn't do anything," he said.